The six items on this page constitute a complete automated CO2 System for planted aquariums up to 75 gallons. For smaller aquariums you can use the Hydor CO20 and CO2 88 Pressurized CO2 Kits (NOT automated). For larger aquariums you would want to use of the larger CO2 Reactors we carry. The larger Reactors are more complex and involve water pumps and more complex CO2 connections.
